Pinch clamps or valves that use a pinching motion to control the flow of a fluid through a compressible tube are known. Actuated pinch valves use an actuator to displace a pinching element against a portion of the outer wall of the compressible tube. The pinching element progressively collapses the outer wall portion against an opposing section of the pinch valve or other support structure to regulate fluid flow through the tube. Due to the separation of the pinching element from the fluid flowing through the compressible tube, cross-contamination is prevented, which renders actuated pinch valves preferable for use in various medical devices, including, for example, dialysis equipment, intravenous systems, blood analyzers, etc.
Pinch valve actuators typically employ an electrical solenoid that is counterbalanced by a spring. The spring applies the force for pinching and solenoid holds the actuator against the spring to open the valve. Thus, when power is applied to the solenoid, the valve is open and the valve is closed by selective deactivation of the solenoid or by loss of power. This functionality serves as a safeguard by halting the flow of fluids when system power is lost. This can be critical in medical treatment systems.